Alternative energy sources have become much more necessary as fossil fuels are depleted and pollute the environment. Wind energy is one of the most cost effective of all types of renewable energy. However, to make wind a viable source of energy or electricity in particular careful design of wind-capturing machines is necessary. A variety of principles of physics are used to create wind turbines that can efficiently capture energy from the wind. Wind turbines can be onshore or offshore.
A wind turbine typically includes a tower, a nacelle supported by the tower and a rotor mounted to the nacelle. The rotor is coupled via a drive train to a generator housed inside the nacelle. The rotor includes a central rotor hub and a plurality of blades mounted to and extending radially from the rotor hub.
A wind turbine typically includes many bearings that provide relative movement between adjacent parts in a relatively efficient, low-friction manner. Bearings typically require lubrication like, e.g., oil or grease to operate in with low friction and prolong their lifetime.
In an exemplary situation of an oil spillage caused by, e.g., leaking blade bearings of a hydraulic blade pitch system, there is a need for absorbing hydraulic oil wasted inside the rotor hub. Thereby, it is a general intention to collect and/or absorb the oil before escaping the rotor hub and before causing environmental damage to the nearest surrounding of the wind turbine.
WO2012/113402 A1 relates to a sealing system for a wind turbine comprising a first component and a second component positioned proximate the first component and movable relative thereto. An absorbent element is secured to the first component and comprises an oil-absorbent material.
An alternative exemplary embodiment of oil absorbing would be the utilization of watercut oil absorbing plates, directly mounted at reinforcement plates of the blade bearings. However, the installation of such kind of absorbing plates is expensive and not satisfying with regard to service and maintenance activities. As a further disadvantage, such absorbing plates cannot be secured or mounted during initial installation or production of a wind turbine as they are hindering the installation of rotor blades during, e.g., erection of the wind turbine.